Gallium Ga 68 DOTA-NeoBOMB1 and Gallium Ga 68 PSMA-R2 PET/MRI in Diagnosing Participants With Recurrent Prostate Cancer

Inclusion Criteria:

* Biopsy proven prostate adenocarcinoma.
* Rising prostate-specific antigen (PSA) after definitive therapy with prostatectomy or radiation therapy (external beam or brachytherapy).

  a. Post radical prostatectomy (RP) - American Urological Association (AUA) recommendation.

  (i) PSA greater than 0.2 ng/mL measured after at least 6 weeks from radical prostatectomy.

(ii) Confirmatory persistent PSA greater than 0.2 ng/mL (total of two PSA measurements greater than 0.2 ng/mL).

b. Post-radiation therapy ? American Society for Therapeutic Radiology and Oncology (ASTRO)-Phoenix consensus definition.

(i) A rise of PSA measurement of 2 or more ng/mL over the nadir.

* Able to provide written consent.
* Karnofsky performance status of \>= 50 (or Eastern Cooperative Oncology Group \[ECOG\]/World Health Organization \[WHO\] equivalent).

Exclusion Criteria:

* Inability to lie still for the entire imaging time.
* Inability to complete the needed investigational and standard-of-care imaging examinations due to other reasons (severe claustrophobia, radiation phobia, etc.).
* Any additional medical condition, serious intercurrent illness, or other extenuating circumstance that, in the opinion of the Investigator, may significantly interfere with study compliance.
* Known allergy, hypersensitivity, or intolerance to the investigational product or its excipients.
* Metallic implants (contraindicated for magnetic resonance imaging \[MRI\]).